Intravenous Immune Globulin (IVIG) as Adjunctive Therapy in Infectious Diseases—Indications, Evidence, Dosing, and Clinical Principles

Intravenous immune globulin (IVIG) is a pooled polyclonal IgG preparation derived from thousands of healthy plasma donors, which provides broad passive humoral immunity alongside significant immunomodulatory effects. In infectious diseases, IVIG occupies a defined role across three clinical contexts: (1) immunoglobulin replacement therapy for primary and secondary antibody deficiencies predisposing to recurrent infection; (2) neutralization of bacterial toxins and superantigens in severe toxin-mediated syndromes; and (3) attenuation of dysregulated host inflammation in conditions such as Kawasaki disease and multisystem inflammatory syndrome in children (MIS-C). Evidence strength varies widely, from robust randomized trial data for Kawasaki disease and primary immunodeficiency to largely observational support for toxic shock and sepsis. This review summarizes established and emerging IVIG indications in infectious diseases, key trial evidence, dosing reference tables, and settings in which IVIG is not indicated.